The present invention relates to aircraft radar systems, and more particularly to an adaptive radar scanning system that adjusts a radar scan range based on factors such as changing aircraft heading to improve the usefulness of radar information during conditions such as aircraft turns.
Modem aircraft are equipped with many on-board safety and diagnostic systems, including a radar system for detecting weather patterns located generally in front of the aircraft. Radar antennas in radar systems typically operate according to a fixed azimuth scanning pattern. In an exemplary system, the antenna scans at a fixed 45 degree per second rate from +90 degrees to xe2x88x9290 degrees and back with respect to the nose of the aircraft. In some modes of operation, this xe2x80x9crevisit ratexe2x80x9d may be even slower, since more sophisticated systems often utilize the radar antenna for other tasks in addition to the traditional weather scan. A typical revisit time (the maximum time required for a point to be successively scanned) is between about 8 seconds and about 30 seconds, with even longer revisit times anticipated for future radar systems that provide additional radar features.
In most situations, these revisit rates are acceptable, since weather patterns do not typically change in sub-minute intervals. However, fixed scanning systems can leave fairly large unscanned regions during a turn, when the heading of the aircraft is changing. For example, in a standard 3 degree per second turn of the aircraft, a revisit time of 8 seconds can leave a region of about 20 degrees in the direction of the turn unscanned, while a revisit time of 30 seconds can leave a region of about 70 degrees in the direction of the turn unscanned. Since the weather patterns in the direction of the turn are exactly what the pilot is interested in, to determine what the weather looks like in the direction the aircraft will be heading, these unscanned regions can be problematic. The pilot can potentially be left with very little time to avoid an inclement weather pattern once the aircraft""s turn has been completed.
It would improve the performance of the aircraft radar system to adaptively adjust the scanning range of the radar antenna to compensate for the changing heading of the aircraft during a turn. Such a system is the subject of the present invention.
The present invention is an adaptive radar scanning system for an aircraft. A radar antenna is angularly movable to scan across a full scan range. A control system operates the radar antenna to scan in an adjusted scan range based on information related to a heading of the aircraft. As a result, the radar system is able to provide more weather information in the direction of a turn, by truncating the scan range of the radar antenna in the direction away from the turn.